Absorbent article having liquid handling member which collapses under high pressures

ABSTRACT

The present invention relates to absorbent articles for retaining body fluids such as urine, menses, or fecal material. In particular, the absorbent article of the present invention comprises a liquid handling member that collapses at a pressure between 2756 Pascal (0.4 psi) and 3447 (0.5 psi) in order to reduce the likelihood of causing skin marking.

FIELD OF THE INVENTION

The present invention relates to absorbent articles for retaining bodyfluids such as urine, menses, or fecal material, and in particular totheir ability to acquire and retain aqueous based materials. Theinvention further relates to disposable absorbent articles such as babydiapers or training pants, adult incontinence products, and femininehygiene products.

BACKGROUND

Disposable absorbent articles such as diapers, sanitary napkins, adultincontinence products, and the like are well known in the art. Sucharticles are used for handling body exudates such as urine, menses,fecal material, and other aqueous body liquids.

It has been a recent trend to provide absorbent articles which compriseliquid handling members of a low density. Such liquid handling membersare capable of rapidly acquiring large volumes of body exudatesdeposited onto the absorbent article. In particular for the handling ofhigh viscosity liquids, it is desired that the liquid handling membershave large open pores. For example such structures are described in WO95/05139 (Roe), in WO 99/25293 (Bast et al.), and in WO 99/25294 (Roe etal.).

On the other hand, liquid handling members having large open poresgenerally do not have planar major surfaces since at least some of thelarge open pores will extend to the surfaces. During use of and articlecomprising such a liquid handling member, the pressure exerted onto thearticle for example by the wearer sitting on the article has to becarried by the remaining parts of the surface. Hence, a relatively highpressure is exerted onto the skin of the wearer at these surface partsleading to a undesirably low level of wearing comfort and ultimately toskin marking.

Hence, it is an object of the present invention to provide a disposableabsorbent article which overcomes the problems posed by the prior artabsorbent articles.

It is a further object of the present invention to provide a disposableabsorbent article comprising a liquid handling member that collapses ata pressure between 2756 Pascal (0.4 psi) and 3447(0.5 psi).

SUMMARY OF THE INVENTION

The present invention provides an disposable absorbent articlecomprising a liquid pervious structured carrier, a liquid imperviousbacksheet at least partially peripherally joined to the structuredcarrier, a liquid storage structure positioned intermediate the topsheetand the backsheet, and a liquid handling structure positionedintermediate the topsheet and the liquid storage structure, the liquidhandling structure having a caliper under a confining pressure of 689Pascal (0.1 psi) of at least 0.5 mm. The absorbent article of thepresent invention is characterized in that the liquid handling structurehas a caliper under a confining pressure of 2756 Pascal (0.4 psi) of atleast 80% of the caliper under a confining pressure of 689 Pascal andthe liquid handling structure has a caliper under a confining pressureof 3447 Pascal (0.5 psi) of less than 80% of the caliper under aconfining pressure of 689 Pascal.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view of an absorbent article embodiment of the presentinvention having portions cut away to reveal the underlying structure,the garment-facing surface of the diaper facing the viewer.

DETAILED DESCRIPTION OF THE INVENTION

The absorbent article of the present invention is described in thefollowing by means of a variety of different embodiments and by means ofa variety of is different features. Further embodiments of the presentinvention may be obtained by combining features of one embodiment withfeatures of another embodiment disclosed herein and/or with otherfeatures disclosed herein. These further embodiments are considered tobe implicitly disclosed herein and hence form part of the presentinvention. It will be apparent to the skilled person that combinationsof certain features may lead to non-functional articles not forming partof the present invention.

Absorbent Article

As used herein, the term “absorbent article” refers to devices whichabsorb and contain body exudates, and, more specifically, refers todevices which are placed against or in proximity to the body of thewearer to absorb and contain the various exudates discharged from thebody. The term “disposable” is used herein to describe absorbentarticles which are not intended to be laundered or otherwise restored orreused as an absorbent article (i.e., they are intended to be discardedafter a single use and, preferably, to be recycled, composted orotherwise disposed of in an environmentally compatible manner). A“unitary” absorbent article refers to absorbent articles which areformed of separate parts united together to form a coordinated entity sothat they do not require separate manipulative parts like a separateholder and liner. A preferred embodiment of an absorbent article of thepresent invention is the unitary disposable absorbent article, diaper20, shown in FIG. 1. As used herein, the term “diaper” refers to anabsorbent article generally worn by infants and adult incontinentpersons and is worn about the lower torso of the wearer. The presentinvention is also applicable to other absorbent articles such asincontinence briefs, incontinence undergarments, absorbent inserts,diapers holders and liners, feminine hygiene garments, and the like.

Diaper

FIG. 1 is a plan view of the diaper 20 of the present invention in aflat-out, state with portions of the structure being cut-away to moreclearly show the construction of the diaper 20. The portion of thediaper 20 which faces the wearer is oriented towards the viewer. Asshown in FIG. 1, the diaper 20 preferably comprises a liquid perviousstructured carrier 24; a liquid impervious backsheet 26; an liquidstorage structure 28, which is preferably positioned between at least aportion of the structured carrier 24 and the backsheet 26; a liquidhandling structure 29 positioned between the structured carrier 24 andthe liquid storage structure 28; side panels 30; elasticized leg cuffs32; an elastic waist feature 34; and a fastening system generallydesignated 40.

Diaper 20 is shown in FIG. 1 to have a front waist region 36, a rearwaist region 38 opposed to the front waist region 36 and a crotch region37 located between the front waist region and the rear waist region. Thediaper 20 further has a first region 81 juxtaposed with the front of thewearer while the diaper 20 is being worn and a second region 82 opposedto the first region 81 and juxtaposed with the back of the wearer whilethe diaper 20 is being worn. The periphery of the diaper 20 is definedby the outer edges of the diaper 20 in which the longitudinal edges 50run generally parallel to the longitudinal centerline 100 of the diaper20 and the end edges 52 run between the longitudinal edges 50 generallyparallel to the lateral centerline 110 of the diaper 20. In FIG. 1 thefirst region 31 is shown as extending from one end edge 35 to thelateral centerline 21 and the second region 32 is shown as extendingfrom the opposing end edge 35 to the lateral centerline 21. For purposesof discussion, the lateral centerline 21 is shown as the boundarybetween the first region 31 and the second region 32 in FIG. 1. However,the boundary between the first region 31 and the second region 32 may bepositioned at other locations, for example closer to one of therespective end edges 52. The first region 31 being juxtaposed with thefront of the wearer may be superior in the handling of urine. The secondregion being juxtaposed with the back of the wearer may be superior inthe handling of fecal material, in particular low-viscosity fecalmaterial.

The chassis 22 of the diaper 20 comprises the main body of the diaper20. The chassis 22 comprises at least a portion of the liquid storagestructure 28 and preferably an outer covering layer including thestructured carrier 24 and the backsheet 26. If the absorbent articlecomprises a separate holder and a liner, the chassis 22 generallycomprises the holder and the liner. (For example, the holder maycomprise one or more layers of material to form the outer cover of thearticle and the liner may comprise an absorbent assembly including astructured carrier, a backsheet, and an liquid storage structure. Insuch cases, the holder and/or the liner may include a fastening elementwhich is used to hold the liner in place throughout the time of use.)For unitary absorbent articles, the chassis 22 comprises the mainstructure of the diaper with other features added to form the compositediaper structure.

FIG. 1 shows an embodiment of the diaper 20 in which the structuredcarrier 24 and the backsheet 26 have length and width dimensionsgenerally larger than those of the liquid storage structure 28 and theliquid handling structure 29. The structured carrier 24 and thebacksheet 26 extend beyond the edges of the liquid storage structure 28to thereby form the periphery of the diaper 20.

While the structured carrier 24, the backsheet 26, and the chassis 22may be assembled in a variety of well known configurations, preferreddiaper configurations are described generally in U.S. Pat. No. 3,860,003entitled “Contractible Side Portions for Disposable Diaper” which issuedto Kenneth B. Buell on Jan. 14, 1975; and U.S. Pat. No. 5,151,092 issuedto Buell on Sep. 9, 1992; and U.S. Pat. No. 5,221,274 issued to Buell onJun. 22, 1993. is Other suitable diaper chassis design are disclosed inU.S. Pat. No. 5,569,232 entitled “Absorbent Article With Multiple ZoneStructural Elastic-Like Film Web Extensible Waist Feature” which issuedto Roe et al. on Oct. 29, 1996; U.S. Pat. No. 5,554,144 entitled“Absorbent Article With Multiple Zone Structural Elastic-Like Film WebExtensible Waist Feature” which issued to Roe et al. on Sep. 10, 1996;U.S. Pat. No. 5,554,143 entitled “Absorbent Article With Multiple ZoneStructural Elastic-Like Film Web Extensible Waist Feature” which issuedto Roe et al. on Sep. 10, 1996; U.S. Pat. No. 5,554,145 entitled“Absorbent Article With Multiple Zone Structural Elastic-Like Film WebExtensible Waist Feature” which issued to Roe et al. on Sep. 10, 1996;U.S. Pat. No. 5,556,394 entitled “Absorbent Article With Multiple ZoneStructural Elastic-Like Film Web Extensible Waist Feature” which issuedto Roe et al. on Sep. 17, 1996. Each of these references is herebyincorporated by reference herein.

The inner surface of the diaper 20 comprises that portion of the diaper20 which is adjacent to the wearer's body during use (i.e., the innersurface generally is formed by at least a portion of the structuredcarrier 24 and other components joined to the structured carrier 24).The outer surface comprises that portion of the diaper 20 which ispositioned away from the wearer's body (i.e., the outer surfacegenerally is formed by at least a portion of the backsheet 26 and othercomponents joined to the backsheet 26) during use.

Aqueous Liquid Handling Performance

The liquid handling performance for aqueous liquids is a key feature ofthe present invention. The term “aqueous liquids” as used hereinincludes but is not limited to body exudates such as urine, fecalmaterial, menses, blood, sweat.

Liquid Acquisition

The term “liquid acquisition” as used herein refers to the rate at whichliquid which is deposited on top of the structured carrier of thepresent invention is absorbed from the surface of the structured carrierinto the absorbent article.

The liquid acquisition performance of the absorbent article of thepresent invention is assessed via the Finished-Product-Acquisition Test.

The absorbent article of the present invention has a liquid acquisitionrate of at least 3.75 ml/s in the first gush, preferably of at least 4ml/s in the first gush, more preferably at least 4.5 ml/s in the firstgush, and most preferably at least 5 ml/s in the first gush. Theabsorbent article of the present invention further has a liquidacquisition rate of at least 0.5 ml/s in the fourth gush, preferably atleast 0.6 ml/s in the fourth gush, more preferably at least 0.8 ml/s inthe fourth gush, and most preferably at least 1.0 ml/s in the fourthgush.

Liquid Rewet

The term “liquid rewet” as used herein refers to already acquired liquidthat is subsequently squeezed out through the structured carrier of aloaded absorbent article under pressure.

The liquid rewet performance of the absorbent article of the presentinvention is assessed via the Collagen Rewet Test and is quantified bythe Skin Hydration value.

The front region of the absorbent article of the present invention has aSkin Hydration value of less than 120 mg, preferably a Skin Hydrationvalue of less than 90 mg, more preferably a Skin Hydration value of lessthan 70 mg, and most preferably a Skin Hydration value of less than 50mg.

Optionally, the back region may have a Skin Hydration value of less than120 mg, preferably a Skin Hydration value of less than 90 mg, morepreferably a Skin Hydration value of less than 70 mg, and mostpreferably a Skin Hydration value of less than 50 mg.

Topsheet Wetness

In order to support the dry touch of the user facing surface of theabsorbent article of the present invention, the absorbent article of thepresent invention preferably has a topsheet wetness of less than 300 mg,more preferably less than 200 mg, even more preferably less than 100 mg,even more preferably less than 50 mg, most preferably less than 25 mgaccording to the Topsheet-Finished-Product-Dryness Method.

High Viscosity Liquid Handling

In addition, the absorbent article of the present invention preferablyprovides high viscosity liquid handling, and in particular liquidhandling of viscous fluid body waste.

As used herein, the term “viscous fluid bodily waste” or “VFBW”generally refers to any waste discarded from the body which has aviscosity of greater than about 10 cP and less than about 2×10⁵ cP at ashear rate of one 1/sec, (at about 35 degrees C.), more particularlybetween about 10³ cP and 10⁵ cP at a one 1/sec shear rate, in acontrolled stress rheometry test using parallel plates on a controlledstress rheometer. (For reference, water is at 1.0 cP at 20 degrees C.and Jif Creamy peanut butter (available from the Procter & Gamble Co.,Cincinnati, Ohio) is approximately 4×10⁵ cP at 25 degrees C. at thissame shear rate).

Storage Under Pressure

Once viscous fluid bodily waste has penetrated the liquid handlingstructure, it is desirable to store or hold the waste away from thewearer during the remainder of the wearing cycle and away from thecaregiver during the changing process. As used herein, the term “store”refers to the physical separation of material deposited in a diaper fromthe body-facing surface of the article such that the material depositedin the diaper is not immediately in contact with or accessible to thewearer's skin. Storage Under Pressure, or “storage,” is measured as theamount of material held in the structure on a unit area basis, asdescribed in the Test Method Section below. If the Storage UnderPressure capacity is too low, the absolute quantity of viscous fluidbodily waste that can be stored away from skin access per unit area ofthe structure will be reduced. Adequate storage capacity is essential toreduce the probability of leakage and the area of skin contaminated byviscous fluid bodily waste because viscous fluid bodily waste that hasbeen stored is less likely to be available to the body-facing surface ofthe structure for leakage and migration within the article.

In preferred embodiments of the present invention the absorbent articleshould include a liquid handling structure having a Storage UnderPressure value greater than about 500 grams per square meter (g/m²) ofthe liquid handling structure of viscous fluid bodily waste. Morepreferably, the liquid handling structure should have a Storage UnderPressure value greater than about 750 g/m² of viscous fluid bodilywaste. Even more preferably, the liquid handling structure should have aStorage Under Pressure value greater than about 1000 g/m² of viscousfluid bodily waste, and most preferably greater than about 1100 g/m² ofviscous fluid bodily waste. Generally, Storage Under Pressure valuesbetween at least about 500 g/m² and about 10000 g/m², and preferablybetween about 750 g/m² and about 10000 g/m² have been found to beacceptable. (These preferred Storage Under Pressure parameters relate tointegrated articles which are preferably evaluated as they are intendedfor use. Accordingly, all of the components or layers of the articleshould be configured as they would be during normal use when themeasurement of their performance is made.)

Retention and Immobilization Under Compressed Inversion

Viscous fluid bodily waste that is accepted by, or penetrates, theabsorbent article is preferably also retained in the diaper away fromthe wearer. One preferred way to retain bodily waste, especially viscousfluid bodily waste, is to immobilize the waste in a location away fromthe wearer. As used herein, the term “immobilize” refers to the abilityof the material or structure to retain stored viscous fluid bodily wasteunder an applied pressure and/or the influence of gravitational forces.Immobilization Under Compressed Inversion, or “immobilization,” may beaccomplished by increasing the waste's viscosity (e.g., by dewatering),by mechanical entrapment (i.e., a surface energy phenomenon driven byincreased surface area of contact of the viscous fluid bodily wasteswith the internal regions of the material or structure) or by any othermeans known in the art. “Immobilization Under Compressed Inversion,” asdescribed further in the Test Method Section below, is measured in termsof the percentage of the viscous fluid bodily waste or analogue thatremains in the structure after the structure is subjected to an invertedpressure cycle, as described below. “Retention Under CompressedInversion”, or “retention,” is an absolute measure of how much viscousfluid bodily waste remains “stored” under stressful usage conditions.

Preferably, the liquid handling structure should have a Retention UnderCompressed Inversion value of greater than about 7.5 g of the viscousfluid bodily waste which penetrates the structure. More preferably, theliquid handling is structure should have a Retention Under CompressedInversion value of greater than about 8.0 g of viscous fluid bodilywaste, and most preferably greater than about 8.5 g of viscous fluidbodily waste after being subjected to the Retention Under CompressedInversion test, as described below. Generally, Retention UnderCompressed Inversion values between at least about 7.5 g and about 100.0g, and between about 8.0 g and about 100.0 g have been found to beacceptable. Under the same conditions, the liquid handling structureshould have an Immobilization Under Compressed Inversion value of atleast 70% of the viscous fluid bodily waste accepted by the liquidhandling structure. More preferably, the liquid handling structureshould have an Immobilization Under Compressed Inversion value of atleast about 80% and most preferably at least about 85% of the viscousfluid bodily waste accepted by the element 120. Generally,Immobilization Under Compressed Inversion values between at least about70% and about 100%, and between about 80% and about 100% have been foundto be acceptable. (These preferred Immobilization and Retention UnderCompressed Inversion parameters relate to integrated articles which arepreferably evaluated as they are intended for use. Accordingly, all ofthe components or layers of the article should be configured as theywould be during normal use when the measurement of their performance ismade.)

Without the appropriate immobilization and retention performance, theeffects of improved acceptance and storage performance may be diminishedbecause the viscous fluid bodily waste may return to the body-facingsurface of the structure, increasing the likelihood of leakage orcontamination of the wearer's skin. Further, immobilization is mosteffective if the structure first accepts the waste and then stores it.Viscous fluid bodily waste that is immobilized prior to being storedaway from the wearer's skin may remain on the structured carrier incontact with the skin. Immobilizing viscous fluid bodily waste which isin contact with the skin can increase the effort required by thecaregiver during the changing/cleaning process and increases thelikelihood of residual, micro-level contamination. “Micro-levelcontamination” refers to waste residue which remains on the skin, but isnot easily visible to the human naked eye. Therefore, it may be helpfulto consider at least three parameters (acceptance, storage, andimmobilization or acceptance, storage and retention) for a givenstructure when determining its utility for effectively managing viscousfluid bodily wastes.

In some embodiments, it may be desirable to provide the diaper 20 withdifferent acceptance performance in different portions of the diaper.This may be accomplished by providing a single structured carrier whichhas been manufactured or treated to have regions of differing acceptancecharacteristics. Further, the structured carrier may be elevated abovethe plane of the body-facing surface of the article so as to be inbetter control of exuded viscous fluid bodily wastes. In someembodiments, it may even be desirable to have the structured carrier incontact with skin of wearer in proximity of the viscous fluid bodilywaste source (e.g., the perianal region).

The trans-topsheet capacity as measured by the trans-topsheet capacitytest as disclosed hereinafter reflects the diapers ability to handlelow-viscosity fecal material. First region 81 and second region 82 ofthe diaper 20 should have a relatively high trans-topsheet capacity.

There is an inverse relationship between the minimum trans-topsheetcapacity necessary to handle low-viscosity fecal material and thesurface area of the diaper 20 having this minimum capacity. As a largerpercentage of the diaper 20 surface area has a trans-topsheet capacitysufficient to handle low-viscosity fecal material, the necessarytrans-topsheet capacity diminishes.

In any case, the first region 81 and the second region 82 of the diaper20 preferably have a trans-topsheet capacity of at least about 300 gramsper square inch provided that an surface area at least 0.02 square meterof the diaper 20 has such a trans-topsheet capacity and preferably atleast 0.03 square meter of the diaper 20 has such a trans-topsheetcapacity.

At least a portion of the first region 81 and at least a portion thesecond region 82 of diaper 20 according to the present inventionpreferably provides a trans-topsheet capacity of at least 300 grams persquare meter, more preferably at least 400 grams per square meter, evenmore preferably at least 500 grams per square meter, still morepreferably at least 600 grams per square meter, and most preferably atleast 700 grams per square meter.

Liquid Storage Structure

Liquid Storage

The liquid storage structure 28 may be any absorbent means which isgenerally compressible, conformable, non-irritating to the wearer'sskin, and capable of absorbing and retaining liquids such as urine andother certain body exudates. As shown in FIG. 1, the liquid storagestructure 28 has a garment surface, a body surface, side edges, andwaist edges. The liquid storage structure 28 may be manufactured in awide variety of sizes and shapes (e.g., rectangular, hourglass,“T”-shaped, asymmetric, etc.) and from a wide variety ofliquid-absorbent materials commonly used in disposable diapers and otherabsorbent articles such as comminuted wood pulp which is generallyreferred to as airfelt. Examples of other suitable absorbent materialsinclude creped cellulose wadding; meltblown polymers including coform;chemically stiffened, modified or cross-linked cellulosic fibers; tissueincluding tissue wraps and tissue laminates; absorbent foams; absorbentsponges; superabsorbent polymers; absorbent gelling materials; or anyequivalent material or combinations of materials.

The configuration and construction of the liquid storage structure 28may also be varied (e.g., the liquid storage structure 28 may havevarying caliper zones, a hydrophilicity gradient, a pore size gradient,a superabsorbent gradient, or lower average density and lower averagebasis weight acquisition zones; or may comprise one or more layers orstructures). The total absorbent capacity of the liquid storagestructure 28 should, however, be compatible with the design loading andthe intended use of the diaper 20. Further, the size and absorbentcapacity of the liquid storage structure 28 may be varied to accommodatewearers ranging from infants through adults.

Exemplary absorbent structures for use as the liquid storage structure28 are described in U.S. Pat. No. 4,610,678 entitled “High-DensityAbsorbent Structures” issued to Weisman et al. on Sep. 9, 1986; U.S.Pat. No. 4,673,402 entitled “Absorbent Articles With Dual-Layered Cores”issued to Weisman et al. on Jun. 16, 1987; U.S. Pat. No. 4,888,231entitled “Absorbent Core Having A Dusting Layer” issued to Angstadt onDec. 19, 1989; and U.S. Pat. No. 4,834,735, entitled “High DensityAbsorbent Members Having Lower Density and Lower Basis WeightAcquisition Zones”, issued to Alemany et al. on May 30, 1989.

Wrap Sheets

The liquid storage structure of the present invention may furthercomprise at least one wrap sheet. The wrap sheet covers the absorbentstructure at least at a part of the surface of the absorbent structure,such that the fluid path from the liquid receiving area to the liquidstorage structure will pass through the web. Thus the meaning of theterm “wrapping” should not be read to mean complete wrapping orenveloping only. An example for such an embodiment can be a wrap-sheetcovering the top surface of the liquid storage structure, and then isbeing tacked down next to the core, such that the side surface can bebut not necessarily have to be covered by the wrap sheet.

In a preferred embodiment, the wrap-sheet covers also other surfaces ofthe liquid storage structure, in one preferred embodiment, it covers allsix surfaces, such that the liquid storage structure is completelyenveloped. Another preferred and more easy to manufacture embodimentcovers the top surface as well as two side surfaces by being foldedaround these to partly of fully cover the bottom surface.

The wrapping of the absorbent member can also be achieved by more thanmore than one wrap-sheet, or by one wrap sheet with different propertiesin different regions thereof. For example, the surface parts of theabsorbent member which are not in the fluid flow path, can have no, ornon-permanent fluid hydrophilicity. Or, a different wrap material can beused in such regions, or the absorbent member materials can there becontained by other elements, such as conventional tissue materials, butalso impermeable sheets, which may at the same time have anotherfunctionality, such as a backsheet material.

Of course, it is an essential requirement, that the absorbent structureand the wrap sheet are in fluid communication with each other, such thatthe fluid flow path, and particularly the capillary transport gradientwill not be interrupted. A preferred embodiment of this is a design,where the wrap sheet and the absorbent structure are in direct contactwith each other—at least for the surfaces as described in the above.

It is generally known in the art, to manufacture suitable wrap sheetsfrom tissue layers, nonwovens, and the like. Preferred nonwovenmaterials to be used for the wrap sheets of the present invention aredisclosed for example in European patent application 98107288.7 (Fuchs).These hydrophilic materials exhibit a low surfactant release to theacquired liquid and hence do not negatively impact the liquid handlingof the absorbent article of the present invention. In order to notnegatively impact the liquid handling of the absorbent article of thepresent invention, a suitable wrap sheet has a surface tension reductionvalue of less than 15 mN/m, preferably less than 12 mN/m, morepreferably less than 9 mN/, even more preferably less than 6 mN/m, andmost preferably of less than 3 mN/m according to the surface tensionreduction test defined hereinafter.

Backsheet

The backsheet 26 is positioned adjacent the garment surface of theliquid storage structure 28 and is preferably joined thereto byattachment means (not shown) such as those well known in the art. Asused herein, the term “joined” encompasses configurations whereby anelement is directly secured to the other element by affixing the elementdirectly to the other element, and configurations whereby the element isindirectly secured to the other element by affixing the element tointermediate member(s) which in turn are affixed to the other element.

For example, the backsheet 26 may be secured to the liquid storagestructure 28 by a uniform continuous layer of adhesive, a patternedlayer of adhesive, or an array of separate lines, spirals, or spots ofadhesive. Adhesives which have been found to be satisfactory aremanufactured by H. B. Fuller Company of St. Paul, Minn. and marketed asHL-1258. The attachment means will preferably comprise an open patternnetwork of filaments of adhesive as is disclosed in U.S. Pat. No.4,573,986 entitled “Disposable Waste-Containment Garment”, which issuedto Minetola et al. on Mar. 4, 1986, more preferably several lines ofadhesive filaments swirled into a spiral pattern such as is illustratedby the apparatus and methods shown in U.S. Pat. No. 3,911,173 issued toSprague, Jr. on Oct. 7, 1975; U.S. Pat. No. 4,785,996 issued to Ziecker,et al. on Nov. 22, 1978; and U.S. Pat. No. 4,842,666 issued to Wereniczon Jun. 27, 1989. Each of these patents is incorporated herein byreference. Alternatively, the attachment means may comprise heat bonds,pressure bonds, ultrasonic bonds, dynamic mechanical bonds, or any othersuitable attachment means or combinations of these attachment means asare known in the art.

The backsheet 26 is impervious to liquids (e.g., urine) and ispreferably manufactured from a thin plastic film, although otherflexible liquid impervious materials may also be used. As used herein,the term “flexible” refers to materials which are compliant and willreadily conform to the general shape and contours of the human body.

The backsheet 26 prevents the exudates absorbed and contained in theliquid storage structure 28 from wetting articles which contact thediaper 20 such as bedsheets and undergarments. The backsheet 26 may thuscomprise a woven or nonwoven material, polymeric films such asthermoplastic films of polyethylene or polypropylene, or compositematerials such as a film-coated nonwoven material. Preferably, thebacksheet 26 is a thermoplastic film having a thickness of about 0.012mm (0.5 mil) to about 0.051 mm (2.0 mils). Particularly preferredmaterials for the backsheet 26 include RR8220 blown films and RR5475cast films as manufactured by Tredegar Industries, Inc. of Terre Haute,Id. The backsheet 26 is preferably embossed and/or matte finished toprovide a more cloth-like appearance. Further, the backsheet 26 maypermit vapors to escape from the liquid storage structure 28 (i.e., bebreathable) while still preventing exudates from passing through thebacksheet 26.

Structured Carrier

The structured carrier 24 of the present invention has a first or innersurface oriented toward the interior of the disposable diaper,specifically oriented toward the liquid storage structure 28, and anopposed second or outer surface oriented toward the skin of the wearerwhen the diaper is worn.

The structured carrier 24 is juxtaposed with, but not necessarilyadjacent the body surface of the liquid storage structure 28, and ispreferably joined to the backsheet 26 or liquid storage structure 28 bymeans such as those well known in the art. In a preferred embodiment ofthe present invention, the structured carrier 24 and the backsheet 26are joined directly to each other in the diaper periphery.

The structured carrier 24 is compliant, soft feeling, and non-irritatingto the wearer's skin. Further, the structured carrier 24 is liquidpervious, permitting liquids (e.g., urine) to readily penetrate throughits thickness. A suitable structured carrier 24 may be manufactured froma wide range of materials, such as porous foams; reticulated foams;apertured plastic films; or woven or nonwoven webs of natural fibers(e.g., wood or cotton fibers), synthetic fibers (e.g., polyester orpolypropylene fibers), or a combination of natural and synthetic fibers.Preferably, the structured carrier 24 is made of a hydrophobic materialto isolate the wearer's skin from liquids contained in the liquidstorage structure 28.

General Properties

Functional Properties

The structured carrier of the present invention is hydrophobic and inorder to minimize liquid retention in the structured carrier and tominimize liquid rewet from the liquid handling structure or the liquidstorage structure back to the skin of the wearer.

Optionally, the structured carrier of the present invention may also beoleophobic in order to minimize liquid retention in the structuredcarrier and to minimize liquid rewet from the liquid handling structureor the liquid storage structure back to the skin of the wearer.

The structured carrier of the present invention has a liquid retentionin the topsheet according to the Liquid-Retention Test definedhereinafter of less than 50 mg , preferably less than 40 mg, morepreferably less than 30 mg, most preferably less than 20 mg for a testliquid having a surface tension of about 62 mN/m.

The structured carrier of the present invention has a liquid retentionin the topsheet according to the Liquid-Retention Test definedhereinafter of less than 150 mg, preferably less than 120 mg, morepreferably less than 90 mg, most preferably less than 70 mg for a testliquid having a surface tension of about 33 mN/m.

The contact angle of the user facing side of the structured carrier ofthe present invention with distilled water having a surface tension ofat least 72 mN/m is at least 90°, preferably at least 100°, morepreferably at least 110°, even more preferably at least 120°, mostpreferably more than 125°. High contact angles reduce the capillarysuction of the pores of the structured carrier. Contact angles of morethan 90° even result in a negative the capillary suction, hencerendering the respective pores water repellent.

Structural Properties

The structured carrier 24 preferably has a plurality of apertures withan is effective aperture size of at least 0.2 square millimeters, morepreferably, the plurality of apertures have an effective aperture sizeof at least 0.5 square millimeters, even more preferably, the pluralityof apertures have an effective aperture size of at least 1.0 squaremillimeters, even more preferably, the plurality of apertures have aneffective aperture size of at least 2.0 square millimeters, and mostpreferably, the plurality of apertures have an effective aperture sizeof at least 3.0 square millimeters. Effective apertures are those whichhave a gray level of 18 or less on a standard gray level scale of 0-255,under the image acquisition parameters described below.

The structured carrier 24 preferably has an effective open area of atleast 15 percent, more preferably the structured carrier has aneffective open area of at least 20 percent, even more preferably, thestructured carrier has an effective open area of at least 25 percent,and most preferably the structured carrier has an effective open area ofat least 30 percent.

A method to determine effective aperture size and open area is describedin the method section.

Manufacturing Techniques

Suitable materials and structures for use as the structured carrier mayinclude apertured nonwoven webs, apertured films, apertured formedfilms, scrims, woven webs, scrim, netting, macroporous thin foams,composites of the aforementioned materials, and the like. There are anumber of manufacturing techniques which may be used to manufacture thestructured carrier 24. For example, the structured carrier 24 may be anonwoven web of fibers spunbonded, carded, wet-laid, meltblown,hydroentangled, combinations or composite laminates of the above, or thelike. Preferred structured carriers 24 include a carded/cardedcomposite, hydroentangled over a wire forming screen and thermallyair-through bonded by means well known to those skilled in the nonwovensart and hydroentanglement of fibrous webs.

Surface Treatment

The structured carrier 24 of the present invention may comprise asurface finish reducing the surface free energy of at least a part ofthe surface of the structured carrier and hence rendering this part ofthe surface even more hydrophobic and eventually oleophobic.

The structured may comprise hydrophobicity gradients in a directionparallel to the major surfaces of the structured carrier to provideindividual liquid handling properties in different regions of thestructured carrier. The structured carrier may also comprise ahydrophobicity gradient in a direction perpendicular to the majorsurfaces of the structured carrier in order to enhance liquid transferthrough the structured carrier.

At least a part of the surface, and in particular of the surface facingthe wearer during use, of the structured carrier 24 of the presentinvention may comprise a surface coating such as a thin fluorocarbonpolymer film. Suitable techniques to obtain such a surface coating arewell known in the art and are described for example in European patentapplication No. 98116895.8, in WO 97/42356 (Gleason) and in WO96/00548(Ouellette). Another suitable surface treatment is a silicone releasecoating from Dow Corning of Midland, Mich. available as Syl-Off 7677 towhich a cross-linker available as Syl-Off 7048 is added in proportionsby weight of 100 parts to 10 parts, respectively. Another suitablesurface treatment is a coating of a UV curable silicone comprising ablend of two silicones commercially available from General ElectricCompany, Silicone Products Division, of Waterford, N.Y., under thedesignations UV 9300 and UV 9380C-D1, in proportions by weight of 100parts to 2.5 parts, respectively. Another suitable treatments includefiber finishs available from Fibervisions of Varde, Denmark, under thedesignations T190 and T198, a fiber finish available from Schill andSeilacher of Bbblingen, Germany, under the designation Silastol FC1760,a melt-in additive available from the Minnesota Mining And ManufacturingCompany, of St. Paul, Minn., USA. Other suitable treatment materialsinclude, but are not limited to, fluorinated materials such asfluoropolymers (e.g., polytetrafluoroethylene (PTFE), commerciallyavailable under the trade name TEFLON®) and chlorofluoropolymers. Othermaterials which may prove suitable for providing regions of reducedsurface energy include Petrolatum, latexes, paraffins, and the like.

The structured carrier 24 of the present invention may compriseshydrophobic and oleophobic polymers. Processes to manufacture suchpolymers and articles therefrom is well known in the art and aredescribed for example in U.S. Pat. No. 3,870,767 (Grimaud).

Optionally, the structured carrier of the present invention may betreated by modulated plasma glow discharge treatments as described inEuropean patent application No. 98116895.8 (D'Agostino et al., P&G caseCM1893FQ) and European patent application No. 98116894.1 (D'Agostino,P&G case CM1894FQ).

Skin Care Composition

The outer surface of the structured carrier may comprise an effectiveamount of a skin care composition which is semi-solid or solid at 20 C.and which is partially transferable to the wearer's skin. In preferredembodiment of the absorbent article of the present invention, theabsorbent article additionally comprises an skin care composition whichis at least partially transferable to the skin of the user during theintended use. Preferably, such an oil-containing composition ispositioned on a user facing surface of the absorbent article. Theoil-containing composition may also be deployed in such a way that it isonly released at the time of intended use such as beingmicroencapsulated.

Skin care compositions suitable for the absorbent article of the presentinvention are described for example in WO96/16682 (Roe et al.)incorporated herein by reference.

Liquid Handling Structure

Properties

Positioning

The liquid handling structure is located between the structured carrierand the liquid storage structure. It is preferred that the liquidhandling structure be operatively associated with the structured carriersuch that fluid bodily waste acquired through the structured carrier mayenter the liquid handling structure. In some alternate embodiments, theliquid handling structure may include a leg cuff, the waistband, a fecalwaste containment pocket, or the like, or may be operatively associatedwith any such features.

Preferably, a substantial portion of the liquid handling structure ispositioned in the first region of the absorbent article and a portion ofthe liquid handling structure is positioned in the second region of theabsorbent article. In preferred embodiments, at least a part of theliquid handling structure is located in the region of the article thatis near the wearer's urethra when worn. At least a part of the liquidhandling structure is preferably located in the region of the articlethat is near the wearer's anal region when worn. This helps ensure thatany waste discharged is deposited on or near the liquid handlingstructure.

Functional Properties

The liquid handling structure of the present invention preferably iscapable of accepting, storing, immobilizing and retaining viscous fluidbodily waste that is accepted and stored by the absorbent article. Thesefunctions are described above in the context of the entire absorbentarticle of the present invention.

In addition, the liquid handling structure may transport viscous fluidbodily waste within the absorbent article 20 in directions generallyparallel to the plane of the backsheet 26. The transport may be active,such that capillary or other forces result in the movement of theviscous fluid bodily waste or components thereof (e.g., free water). Inother embodiments, the transport may be passive whereby viscous fluidbodily waste or components thereof move through the structure under theinfluence of externally applied forces, such as gravity, wearer pressureor wearer motion. In the case of passive transport, the liquid handlingstructure should have relatively large, interconnected channels, or thelike, such that the viscous fluid bodily waste may readily move throughthe structure with minimum energy input.

The liquid handling structure of the present invention preferably doesnot reduce the surface tension of a liquid when the liquid handlingstructure is in contact with that liquid. Where needed, it is desirableto either use intrinsically hydrophilic materials such as cellulosicfibers, polyester fibers, or the like or to treat the hydrophobicmaterials with surfactants which are not easily released into theliquid.

Structural Properties

The liquid handling structure of the present invention preferably has aratio of basis weight to uncompressed caliper of less than 100 grams persquare meter per millimeter, i.e. the liquid handling structure has anopen structure in order to readily accept body exudates such as urine,menses, faeces, and the like. More preferably, the liquid handlingstructure of the present invention has a ratio of basis weight touncompressed caliper of less than 90 grams per square meter permillimeter. Yet more preferably, the liquid handling structure of thepresent invention has a ratio of basis weight to uncompressed caliper ofless than 80 grams per square meter per millimeter. Most preferably, theliquid handling structure of the present invention has a ratio of basisweight to uncompressed caliper of less than 70 grams per square meterper millimeter. Liquid handling structures having a ratio of more than100 grams per square meter per millimeter may provide a sufficientopenness to readily accept high viscosity liquids such as faeces andmenses.

The liquid handling structure generally has a basis weight between 5 and500 grams per square meter. Liquid handling structure having a basisweight of less than 5 g/m² will not be able to provide the desiredresiliency and compression resistance. Liquid handling structure havinga basis weight of more than 500 g/m² will add unwanted weight to theabsorbent article which may cause discomfort by the wearer.

The liquid handling member of the absorbent article of the presentinvention overcomes the skin marking problems of the prior art liquidhandling members by collapsing in those areas where high pressure isexerted onto the liquid handling member by the wearer during use. It hasbeen found that the void volume contained in those areas which arelocated outside the high-pressure regions is sufficient to acquire andstore most loadings with high viscosity liquids. In addition, highviscosity liquids initially stored in a high-pressure region will beautomatically moved into a low-pressure region when external pressure isapplied to the high-pressure region.

Therefore, the liquid handling member of the present invention isdesigned to sustain high void volumes under low pressures up to 2758Pascal (0.4 psi) and is further designed to collapse under highpressures of 3447 Pascal (0.5 psi) and above. Under a confining pressureof 2758 Pascal (0.4 psi), liquid handling member of the presentinvention has a caliper of at least 70 percent of its caliper under aconfining pressure of 689 Pascal (0.1 psi), preferably of at least 75percent, more preferably of at least 80 percent, even more preferablyof. at least 85 percent, most preferably of at least 90 percent. Under aconfining pressure of 3447 Pascal (0.5 psi), the liquid handling memberof the invention has a caliper of less than 60 percent of its caliper ona confining pressure of 689 Pascal (0.1 psi), preferably of less than 50percent, more preferably of less than 45 percent, even more preferablyof less than 40 percent, most preferably of less than 35 percent.

To provide sufficient void volume in the low-pressure regions, thecaliper of the liquid handling member of the present invention under aconfining pressure of 689 Pascal (0.1 psi) is at least 0.5 mm,preferably is at least 0.75 mm, more preferably at least 1.0 mm, evenmore preferably at least 1.25 mm, most preferably at least 1.5 mm. Thesurface area of the body facing surface of liquid handling member of thepresent invention preferably is at least 100 square centimeters, morepreferably 200 square centimeters, and most preferably 250 squarecentimeters. The aforementioned values are for babies of about 6 to 9kilograms may need to be adapted for other sizes.

The term “caliper” of a member as used herein refers to the distance oftwo planar, parallel surfaces in the z-dimension whereby the two planarsurfaces confine the member under a defined confining pressure such asfor example 689 Pascals (0.1 psi) and whereby both confining surfacesare perpendicular to the z-dimension of the member. Generally, thez—axis is taken to be perpendicular to the two major surfaces of themember whereby the member is disposed in the absorbent article such thatits major surfaces of parallel to the major surfaces of the absorbentarticle i.e. parallel to the body facing surface and to the garmentfacing surface of the absorbent article.

“Another key property is the resiliency of the liquid handling structure29. In order to remain open, the liquid handling structure 29 must havea sufficient resiliency to withstand she forces of packaging and thoseapplied by the wearer. The term “resiliency” as used herein refers tothe percentage of recovered caliper after the liquid handling structurehas been temporarily compressed under a defined pressure. Preferably,the liquid handling structure 29 has a resiliency of as least 50% after30 second under an applied pressure of 1 Newton/cm², more preferably,the liquid handling structure 20 has a resiliency of at least 75% after30 seconds under an applied pressure of 1 Newton/cm², most preferably,the liquid handling structure 29 has a resiliency of at least 85% after30 seconds under an applied pressure of 1 Newton/cm².”

“In order to not negatively impact the liquid handling of the absorbentarticle of the present invention, the liquid handling structure has asurface tension reduction value of less than 15 mN/m, preferably lessthan 12 mN/m, more preferably less than 9 mN/m, even more preferablyless than 6 mN/m, and most preferably of less than 3 mN/m according tothe surface tension reduction test defined hereinafter.”

Structure of the Liquid Handling Structure

The liquid handling structure may be any material or structure capableof accepting, storing, and immobilizing bodily exudates, as describedabove. Thus, the liquid handling structure may include a single materialor a number of materials operatively associated with each other.Further, the liquid handling structure may be integral with anotherelement of the diaper 20 or may be one or more separate elements joineddirectly or indirectly with one or more elements of the diaper 20.Embodiments are contemplated wherein the liquid handling structureincludes at least a portion of the core 28.

Suitable Materials

Suitable materials for use as the liquid handling structure may includelarge cell open foams, macro-porous compression resistant nonwovenhighlofts, large size particulate forms of open and closed cell foams(macro and/or microporous), highloft nonwovens, polyolefin, polystyrene,polyurethane foams or particles, structures comprising a multiplicity ofvertically oriented looped strands of fibers, liquid storage structurestructures described above having punched holes or depressions, and thelike. (As used herein, the term “microporous” refers to materials whichare capable of transporting fluids by capillary action. The term“macroporous” refers to materials having pores too large to effectcapillary transport of fluid, generally having pores greater than about0.5 mm in diameter and more specifically, having pores greater thanabout 1.0 mm in diameter.) The liquid handling structure, or any portionthereof, may include or be coated with a lotion or other knownsubstances to add, enhance or change the performance or othercharacteristics of the element.

A suitable liquid handling member can be obtained for example bysubmitting a nonwoven web material (basis weight about 20 grams per m²to about 60 grams per m²) comprising polyester fibers between 3 denierand 9 denier to the process defined in EP patent application 99124637entitled “Method and apparatus for longitudinally corrugating a webmaterial” filed in the names of Dziezok et al. (P&G case CM2251) orother corrugating processes well known in the art such as creping, ringrolling, and the like. Another suitable liquid handling member may beobtained by using corrugation plates. The above nonwoven web material oranother suitable nonwoven web material can be corrugated this way. Thecorrugation plates can have 6 to 12 loops per inch and a loop height ofabout 2 to 4 mm. For fixing the corrugated structure of the nonwovenweb, the web materials may be kept between the corrugation plates at asuitable temperature of for example about 60° C. for e.g. about 4 hours.

METHODS

“Test methods suitable for measuring the properties described herein aredefined in U.S. Pat. No. 6,635,801, this document being incorporated byreference herein.”

What is claimed:
 1. An disposable absorbent article comprising a liquid pervious structured carrier, a liquid impervious backsheet at least partially peripherally joined to said structured carrier, a liquid storage structure positioned intermediate said structured carrier and said backsheet, and a liquid handling structure positioned intermediate said structured carrier and said liquid storage structure, said liquid handling structure having a caliper under a confining pressure of 689 Pascal (0.1 psi) of at least 0.5 mm, and having a resiliency of at least 50% after 30 seconds under an applied pressure of 1 Newton/cm², wherein said liquid handling structure has a caliper under a confining pressure of 2756 Pascal (0.4 psi) of at least 80% of said liquid handling structure's caliper under a confining pressure of 689 Pascal and said liquid handling structure has a caliper response to a change in confining pressure from 689 Pascal to 2456 Pascal that is less than a caliper response to a change in confining pressure from 2456 Pascal to 3447 Pascal (0.5 psi) whereby said liquid handling structure has a caliper of at a confining pressure of 3447 Pascal that is less than 60% of said liquid handling structure's caliper under a confining pressure of 689 Pascal.
 2. A disposable absorbent article according to claim 1 said disposable absorbent article having a transverse centerline, a first region forward of said transverse centerline being positioned adjacent to the front waist region of the wearer during use, and a second region backward of said transverse centerline being positioned adjacent to the back waist region of the wearer during use wherein at least a substantial part of said liquid handling structure is positioned in said first region.
 3. A disposable absorbent article according claim 1 said disposable absorbent article having a transverse centerline, a first region forward of said transverse centerline being positioned adjacent to the front waist region of the wearer during use, and a second region backward of said transverse centerline being positioned adjacent to the back waist region of the wearer during use wherein at least a substantial part of said liquid handling structure is positioned in said second region.
 4. A disposable absorbent article according to claim 1 wherein said structured carrier comprises an apertured nonwoven web material having a plurality of apertures, said apertures having a surface area of at least 0.2 mm².
 5. A disposable absorbent article according to claim 1 wherein said disposable absorbent article has a front region skin hydration value of less than 100 mg.
 6. A disposable absorbent article according to claim 1 wherein said disposable absorbent article has a storage under pressure capacity of at least 800 g/cm². 